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Increment A to B or ZZ to AAA - only works on capitol ASCII letters
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| defmodule Tallyj.StringExtensions do | |
| @moduledoc """ | |
| This module provides a function that will take a uppercase ASCII letter and | |
| return the next logical value. Wrapping back to A when Z is provided. | |
| Examples: | |
| next("A") | |
| => "B" | |
| next("QA") | |
| => "QB" | |
| next("QZ") | |
| => "RA" | |
| """ | |
| def next(string) when is_binary(string) do | |
| val = next(string |> String.to_char_list |> Enum.reverse, []) | |
| to_string(val |> Enum.reverse) | |
| end | |
| defp next([letter | rest], acc) do | |
| new_letter = next_letter(letter) | |
| next({new_letter, Enum.count(rest)}, rest, acc) | |
| end | |
| defp next([], acc) do | |
| acc | |
| end | |
| defp next({65, 0}, rest, acc), do: next(rest, [[65, 65] | acc]) | |
| defp next({65, _}, rest, acc), do: next(rest, [65 | acc]) | |
| defp next({ltr, _}, rest, acc), do: [[ltr | acc] | rest] | |
| defp next_letter(value) when value >= 90, do: 65 | |
| defp next_letter(value), do: value + 1 | |
| end |
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I tried with this version to be a little more pattern match with functions instead of a case. Logically still the same but implementation is quite different?